Use the time out Method if they need it.
Sounds like they are egging each other on,dont worry about it and dont feed into it unless you are going to laugh and giggle with them, ignore the whining, disract them with lots of Games and activities so they are not bored, Sports and Fun.This is all natural behavior in Twins and kids of this age in General,and very often one Twin is the Ring leader. They sound Great Good Luck